The invention relates to tow trucks of the type in which the truck is movable along a selected path by engagement of a suitable tow pin mounted on the truck with a driving conveyor mounted in a channel in the supporting floor below the truck.
Such trucks have been provided with vertically movable tow pins which have been mounted at various positions along the truck body, usually at the front end. Such trucks have also been provided with front bumpers of various design and with interconnecting mechanisms by which the tow pin can be lifted out of engagement with its driving conveyor in response to engagement of a front bumper with an obstacle encountered by the truck during its forward movement. In some cases the obstacle may be another truck, and such bumpers are therefore sometimes referred to as accumulation bumpers, since they are designed to stop and accumulate all of the trucks moving along the conveyor, if the leading truck encounters an obstacle.
Some of the prior constructions for this purpose are shown in such patents as Burrows U.S. Pat. No. 3,027,850 and Goodrich U.S. Pat. No. 3,148,634.
In some installations such as warehouses, where large numbers of tow trucks are used, it is desirable to keep the total length of the truck to a minimum. Thus, there is a continuing need for improved arrangements of tow pin assemblies and accumulation bumpers, in which these members are arranged and provided with mechanical interconnections which permit the tow pin to be located at the front of the truck, but with minimal forward extension of the total truck length.